<?php
require_once 'Zend/Filter/Interface.php';

class My_Filter_Float implements Zend_Filter_Interface
{
    /**
     * Defined by Zend_Filter_Interface
     *
     * Returns (int) $value
     *
     * @param  string $value
     * @return integer
     */
    public function filter($value)
    {
    	$value = str_replace(",", ".", $value);
    	
        return (float) $value;
    }
}